A dramatic scene unfolded off the coast of Argentina this weekend when naval authorities caught a Chinese vessel illegally fishing in their waters. They pursued, even firing on the vessel:

As you can see, the authorities announce their intention to fire at the ship, and when the ship doesn’t respond they fire warning shots at the vessel. This may seem like an extreme step to take, but illegal fishing is a serious problem — especially in Argentina.

The seas around Argentina have recently become a hotspot for illegal fishing. This is partly because of the richness of marine life that lives there. Every day, somewhere between 200 and 500 fishing vessels from countries like China and South Korea set up shop here. This practice is called IUU, or illegal, unreported and unregulated fishing.

So what’s the issue? Surely there are more fish in the sea than fishing vessels, right? If fishing practices continue as they are, then the meaning of that phrase might change completely.

These fishing boats use unsustainable fishing practices that cause a range of problems — they could net in sea turtles or sharks, they take too many fish without letting the area recover, they dump waste into the ocean, etc. These habits cause worldwide damage to marine life and ocean health.

There is also a hidden problem lurking behind IUU. Because these vessels move around under the radar and internationally, they are hotspots for human trafficking, drug dealing and arms trading. So while it’s a big issue for the ocean, it’s an even bigger issue for many other reasons.

Shooting warning shots at that fishing vessel probably seems a lot more reasonable now! Argentina is working to crack down on the amount of fishing vessels in their waters and chase them away as they do in this video with a range of aggressive tactics. But until the nations that are allowing (and even encouraging) vessels to overfish this area also work on the issue, it will continue to be a problem.